This invention relates to swivel or ball joints for a well string to provide a continuous control or operating fluid passage therethrough in addition to the main bore through which drilling operations are performed.
In the prior art, multi-passage connectors or joints have been utilized which have tubes connecting to opposite ends of passages through the ball, such is shown in U.S. Pat. No. 3,957,291. To maintain continuous flow through the main bore and additional passages, the bending and rotational movement of the joint was limited because the tubes have a limited length and flexibility and rotation is limited to avoid misconnection of tubes across the joint. In addition, the prior art has conduits spanning the exterior of the joint which are not protected by a housing, are bulky and have limited flexibility. These exterior conduits can be subject to breakage by other tools being used or if the joint is in a marine riser pipe by operations around a riser pipe.